Personal computers were designed for interactive use primarily by only one person at a time. Accordingly, a typical personal computer has but one monitor, a single user pointing device such as a mouse, and one keyboard. Although some games enable multiple input devices to be employed by two or more users in playing on a single personal computer, a typical multi-player game is played on a game computing device that is specifically designed for multiple players, or over a network, with each player using a different personal computer or gaming computing device. Interactions between multiple personal computer users running the same software application thus typically occur through communications over local area networks (LANs) or via the Internet, and not on the same personal computer.
Computing devices designed for multiple users can provide a significantly different level of interactivity between users and will normally use a television monitor to provide the larger display size to enable several people to readily view the display at the same time. Multi-user applications provide an opportunity for players to interact with each other while playing a game and thus improve the level of enjoyment. However, multi-user applications are not limited to electronic games. A multi-user platform running a spreadsheet program or a word processing program, for example, can enhance productivity by enabling a plurality of users to collectively collaborate more effectively on the same computing device in regard to a document or file that is being created or edited.
One of the most significant issues in providing a multi-user computing platform is ensuring that the display can readily be viewed by all of the users. Although a conventional large monitor or television screen might do for viewing graphic images, or text that is enlarged, smaller graphic icons and smaller font text will not readily be visible to a plurality of users who must be several feet away from the monitor or screen. One solution to this problem would be to use a projection display that is horizontal so that the users can be seated or stand around the display and be sufficiently close to the display screen on which images are projected to readily view smaller icons and other images, and fonts. Although a rectangular or round display that is horizontal enables the users to be positioned closely around the display at different sides, the orientation of text and other information presented on the display will be partially or wholly inverted for some of the users located on one side of the display if presented in the desired orientation for users on the other side of the display.
In software applications intended to interact with a plurality of users at one time on a single computing device, information will often be displayed that is intended to be viewed only by a specific user at one time, but which need not be oriented for others to view. Without means of identifying the location of each user, an application simply can not display information specifically for an intended user that is properly oriented to be viewed by that user, if the users are located at different positions around the horizontal display. What is clearly needed is a way to determine where each user is located so that information intended to be presented to a specific user can be oriented properly when displayed on a horizontal display surface.